Usually, such a gas generator contains a housing with a combustion chamber formed therein, into which chamber a pyrotechnic solid propellant is filled. To activate the solid propellant, an igniter is provided which is inserted into an opening of the housing and projects into the combustion chamber. In the wall of the housing delimiting the combustion chamber there are several outflow openings for the gases which are released,on combustion of the propellant. These gases are then supplied to the safety device, in particular to an inflatable gas bag or to a knee protector which is able to be activated pneumatically.
In recent times, it has been proposed to construct the gas generator housing from plastic, in particular from fibrereinforced plastic, to save weight. A proposal for the construction of gas generators with a plastic housing has been described for example in the thesis written by Frau Karen Reichart entitled "Airbag-Gasgeneratorgehause aus faserverstarktem Kunststoff", University of Rostock, Faculty of Mechanical Engineering and Marine Technology, Engineering Institute, published in September 1995. In this thesis, reference is already made to the fact that gas generator housings formed from fibre-reinforced plastic require particular measures to prevent an electrostatic charging. In this context, it is proposed in the said thesis to provide the gas generator housing either with a steel casing or else to metallize it galvanically. These measures can indeed reduce the high surface resistance of the plastic housing. However, they require additional components and/or production steps in the manufacture of the gas generator and are therefore not able to be realized at a favourable cost.
From the DE-C2-38 24 162 it is known, in addition, to pack the solid propellant in an airtight manner by means of an aluminium foil, for protection against moisture, a detection of any leaks being made possible by evacuating the aluminium foil.
There is therefore still a need for gas generators which are able to be produced at a favourable cost with a plastic housing, the pyrotechnic components of which are protected from ignition by electrostatic charge and its conductive discharge.